Pneumatic device for separating the uppermost sheet from a pile in sheet feeding apparatus



Aug. 7, 1962 G. SPIESS 3,048,392

PNEUMATIC DEVICE FOR SEPARATING THE UPPERMOST SHEET FROM A PILE IN SHEETFEEDING APPARATUS Filed 001;. 14, 1959 2 Sheets-Sheet l Ticrfi.

INVENTOR. GEORG SP! ESS BY 4mm 5. Wain ATTORNEY Aug. 7, 1962 3 048,392

G. SPIESS PNEUMATIC DEVICE FOR SEPARATING THE UPPERMOST SHEET FROM APILE IN SHEET FEEDING APPARATUS Filed Oct. 14, 1959 2 Sheets-Sheet 2 &

INVENTOR. GEORG SP|E5S BY Mafia 5. (Mu/ k ATTORNEY nit tates PNEUMATICDEVICE FOR SEPARATWG THE UHERMUST SHEET FROM A FILE TN SHEET FEEDWGAPPARATUS Georg Spiess, 9 Possartstrasse, Munich, Germany Filed Get. 14,1959, er. No. 846,500 Claims priority, application Germany Oct. 15, 19581 Claim. (ill. 27127) The separation and lifting of the uppermost sheetfrom a pile is generally effected in known sheet feeding apparatus bymeans of a suction nozzle, of which various types or constructions areknown, which engages and lifts the sheet by a suction cup.

In these circumstances, the problem is to remove the lifted sheet fromthe suction nozzle for the purposes of further feeding said sheet. Ifhigh feed speeds are required, as is the case especially in modernfolding machines, then even where intensive throttling of the suctionair and corresponding reduction of the suction effect is achieved at themoment of removal of the sheet, the

removal of the sheet from the suction nozzles causes inevitableobstructions and hence delays in the travel of the sheet, in consequenceof the friction between the sheet and the nozzle suction surface thathas to be overcome during the removal.

The object of the invention is to eliminate this friction and this isachieved by mounting a suction cylinder so as to be freely rotatable ona part of the machine which performs a lifting and lowering movement,and by providing known means of transport which remove the sheet fromthe freely rotatable suction cylinder by its movement in the desiredtake-off direction, e.g. towards a subsequent processing machine.

The raising and lowering of the suction cylinder which will be equippedwith a suction chamber may be effected in known manner by suitablemechanical driving means. The suction cylinder is preferably mountedrotatably on a telescopic device of a form already known in relation toseparating devices using suction cups, so that suction acting on thesuction cylinder when the suction openings therein are closed by a sheetadhering thereto, causes raising of the cylinder.

In consequence of the fact that, in accordance with the invention, thepneumatically acting separating and lifting element for the uppermostsheet is formed by one or more suction cylinders which are freelyrotatable (preferably on ball-bearings), the removal of the sheet duringits further feed is greatly facilitated and is almost completely free offrictional resistance at the point of contact of the sheet on theseparating means, because the separating means formed by the cylindercan rotate to follow the sheet. To this end, the suction cylinder ismade with the minimum possible mass.

Further features and advantages of the invention will be apparent fromthe following description of the exemplified embodiment shown in thedrawings, in which:

FIG. 1 shows a suction cylinder and the appertaining pneumatic liftingdevice in its two end positions, in side elevation,

FIG. 2 shows the same device turned through 90 and in vertical section,

FIG. 3 is a side view showing the arrangement of the pneumatic devicefor separating and lifting the uppermost sheet adjacent a driven suctionwheel which serves as feed means.

In the drawings a suction idler roller or cylinder 3, which is equippedwith orifices or perforations 1 on its outer curved surface 2 isjournalled on a shaft 5 by means of a ball-bearing 4-. This bearingshaft 5 is lateral y fastened in the lower end of a guide cylinder orsleeve 6 of a lifter mechanism, which slides on a piston 7, into thelower end of which a suction line 8 discharges. The latter is connectedby way of the cyiinder 6 to an elbow 9 and one limb of this elbow 9forms a suction chamber 10 situated within the suction cylinder 3.

To limit the upward stroke of the guide cylinder 6 and consequently thepossible vertical movement of the suction cylinder 3, use is made of afixed upper stop 11, which is constructed on the suction line and whicha collar 12 on the guide sleeve 6 encounters at the end of the stroke.Lower stroke limiting means comprises an arm 14 disposed adjacent thepiston 7 and which is removable or adapted to swing out away from thepiston 7 after a screw 13 has been released. A hook-shaped end 15 on thearm 14 engages with the collar 12 of the guide sleeve 6.

A stop formed by an inclined surface 16 and controlling a tappet 17 of avalve 18 is also provided at the upper edge of the guide sleeve 6. Thevalve 18 actuates, in known manner, a pile transport or raising devicewhich operates by means of suction. This arrangement affords theadvantage that the otherwise necessary pile sensing means for thecontrol of the pile transport is now controlled by the suction cylinderor the mechanism whereon the wheel is carried and is actuated accordingto the position of the suction cylinder 3 on the surface of the pile.

FIG. 3 shows the application of the pneumatic separating and liftingdevice just described to a sheet feeding apparatus operating with adriven suction wheel 22 which serves as feed means. In this case, thepneumatic separating and lifting device is disposed directly in front ofthe suction wheel 22 in the direction of travel of the uppermost sheetwhich is indicated at 21. This affords the advantage that whenlarge-format sheets 21 are to be processed, "contact thereof against thesuction wheel 22 is always ensured. it easily happens that the uppermostor topmost sheet would, hitherto, be liftedonly at its rear edge byconventional separating nozzles 19 and carried by blast air emergingfrom blast nozzles 29, does not dependably come into contact by itsfront part against the suction wheel 22, and this frequently rendersnecessary readjustment of the suction wheel 22. These complications areobviated according to the invention by the fact that the pneumaticlifting device 3, 7 disposed in front of the suction wheel 22 ensuresthat the front part of the sheet is lifted also until it bears againstthe suction wheel 22, the suction cylinder 3 of the lifting device beingadjusted with its lower edge at a somewhat higher level than the loweredge of the suction wheel 22.

In the exemplified embodiment shown in FIG. 3, the separating suctionnozzle 19 may, if desired, be replaced by a pneumatic separating andlifting device 3, 7 of the construction according to the invention. Onthe other hand, a separating nozzle 19 would not be usable conversely asan auxiliary device beside the conveying suction wheel 22-, because theremoval would be obstructed by friction of the sheet at the suctionnozzle, and in the case of printed sheets, the print would be smearedpractically over the entire length of the sheet.

I claim:

A pneumatic device for separating the topmost sheet from a stack ofsheets, comprising a support; a stack of sheets on said support; asuction idler roller rotatable on said support about an axis and formedwith a plurality of circumferentially spaced suction orifices; liftingmeans for moving said roller on said support in a vertically eX- In thecase of largeformat sheets aose, sea

References titted in the file of this patent UNITED STATES PATENTSBroadrneyer July 26, 1927 Dausmann Mar. 24,1936 Baker et al Feb. 15,1944 Pope July 1, 1952 Mitchell July 14, 1953 Layden Feb. 24, 1959

